\section{Requirements}

\subsection{Scientific Requirements}

\subsubsection{Support \htmlref{no-leap}{glos:noleap} and Gregorian calendars}

\subsubsection{Provide the following calculations:} 

\begin{itemize}

\item Given a date, compute a new date that is either earlier or later by a specified time interval.

\item Given two values of date compute the time interval between them.

\item Verify whether or not one date is later than another.

\item Provide \htmlref{calendar day}{glos:calendarday} given date.

\end{itemize}

\subsubsection{Handle time intervals to a precision of 1 second}

\subsubsection{Handle time intervals with a range of 20,000 years} 
  
\subsubsection{Date to string conversion}





